The men were arrested Friday night under the Terrorism Act on a highway south of the city of Preston, Lancashire police said.

What the men were planning was not linked to any imminent domestic threat, said Stefan Jarmolowicz, spokesman for the North West Counter Terrorism Unit. But he added, "we don't arrest people under the Terrorism Act lightly."

Only three of the men, aged between 26 and 36, remained in custody Saturday, police said. The others were released without charge.

The arrests are part of an ongoing intelligence-led investigation by Lancashire police and the North West Counter Terrorism Unit, which is run by the nearby Greater Manchester Police, officials said.

The arrests were based on intelligence from international agencies such as Interpol, Jarmolowicz said.

During the next few days, counter-terrorism officers will help Lancashire police conduct searches of homes in the area, Jarmolowicz said. Five houses in the town of Burnley will be searched Saturday, police said.

"We will endeavor to carry out any searches as quickly as possible to minimize impact on the area concerned," said Chief Superintendent Neil Smith of the Lancashire police.

"However, inquiries of this nature are complex and may take time to resolve. I would like to thank local residents affected by these searches for their cooperation and ask that they remain patient."